1. Field of the Invention
This invention relates to valves for controlling liquid flow, and particularly to a new and improved valve which may be either manually or fluid (e.g., hydraulically) operated.
2. General Description of the Prior Art
All valves employ some form of element which operates either linearly or in a rotary fashion to impinge on, and finally close, an element orifice. When in an open state, the element, e.g., a ball with an opening aligned in the direction of flow, or some form of gate which is retracted to the side of the orifice, all tend to be effected by the material passing through the valve. In the case of pot ash, sulfur solution, and a number of others, the effect is that there is a build-up of material on the valving element which adversely affects operation in two respects. One, it tends to reduce the size of effective orifice, thus flow performance is impaired; and two, build-ups tend to prevent complete valve closure. More generally, existing valves have certain other well recognized problems, at least for certain operations. For example, they are often too bulky for location in confined spaces. Second, being large, they are often quite costly. And third, they are often difficult and expensive to remotely control. For example, the operation of a ball valve or butterfly valve requires a crank attached to the valve and a hydraulic cylinder positioned significantly outboard of the valve to operate the crank.
Accordingly, it is an object of this invention to provide a new and improved valve which eliminates the build-up problem, is extremely compact, and includes built-in means for remote control.